John's homebrew pages

Microwave 50Ω load

Another deviation from the main project!

I had a suitable dummy load for HF, that even works reasonably well at 144MHz, but I couldn't hope that it would have anything near a match at microwave frequencies. So I needed to build something. I was very fortunate to come across a power resistor expressly designed for this purpose in a piece of surplus microwave equipment; it just needed to be built into a suitable heat sink. I decided to mount it, and a SMA connector, on a piece of copper, which is in turn bolted down to an old heatsink from a PC processor cooler. A few holes needed to be drilled and tapped, but it's quite simple.

microwave load components

Here it is assembled; it would be nice to test it properly to see what frequency it works up to, but for now it will at least be better than the resistors in a can of oil that I use at HF.

microwave load assembled